The backbone of Mansfield Park is based around the marriages of sisters Lady Bertram, Mrs. Norris, and Mrs. Price. Each of these sisters marries a man from a different social class.
Lady Bertram marries an extremely wealthy baronet Sir Thomas Bertram; Mrs. Norris marries a clergyman that makes a decent living; and Mrs. Price marries a naval lieutenant, who is injured shortly after they marry causing his career to end with living in poverty.
This tale revolves around Fanny Price, who lives in poverty until being sent to live with her wealthy Aunt Bertram.
While received warmly at first, what unfolds is a life of cold neglect and further trouble in her new lifestyle.